Patent GB-1040771-A (GB)
Title: Improvements in anti-skid devices for vehicle brakes
Inventor: LAURIE WILLIAM DAVID
IPC: B60T8/74
Filed: 1963-02-26
Abstract: 1,040,771. Anti-skid braking devices. GIRLING Ltd. April 17, 1964 [Feb. 26, 1963], No. 7647/63. Heading F2F. In an anti-skid device for vehicles of the kind in which a flywheel is coupled by balls and ramps to a member driven by a wheel of the vehicle or by a part of the vehicle transmission, the balls engaging a continuous annular surface on the flywheel, whereby on excessive retardation of the wheel or transmission member the flywheel tends to overrun the driven member which is moved to relieve the braking pressure. Provision is made for the incorporation of an inertia mass separate from the flywheel and sensitive to linear deceleration of the vehicle. The anti-skid device is mounted on the vehicle with the axis of the spindle 11 which is driven from a wheel of the vehicle or from a part of the transmission to the wheel by any convenient means, at right angles to the longitudinal axis of the vehicle, the housing 10 of the device being secured to a stationary part of the vehicle. When the vehicle is travelling normally the parts are in the position shown in Fig. 1 wherein orifices 36 provided in the spindle 11 are adapted to be closed by a sleeve member 27 which is mounted on the spindle and rotates with it, the flywheel 22 being constrained by the balls 29 to rotate with and at the same speed as the spindle 11 and the sleeve member 27. A weighted arm 39 pivoted in the housing at 40 on an axis parallel to that of the spindle (Fig. 2, not shown) is adapted to swing in a plane parallel to the longitudinal axis of the vehicle such that a friction member carried by the arm is adapted to engage a portion of the cylindrical outer surface of the flywheel 22. With the vehicle travelling normally, due to the inertia mass of the weighted arm 39 the friction member is held out of engagement with the flywheel and up to a vehicle deceleration of 0À3 g. no overrun of the flywheel 22 occurs. On good road surfaces, the inertia mass of the weighted arm 39 causes the flywheel 22 to be decelerated when vehicle deceleration is above 0À3 g. As the road wheels are decelerating the sleeve 27 decelerates but relative rotation of the sleeve 27 and the flywheel does not occur so that the road wheel brake pressure is not affected. On poor road surfaces, vehicle deceleration may reach 0À3 g. and cause operation of the inertia mass to decelerate the flywheel but because of poor road wheel adhesion the wheel angular deceleration and hence the angular deceleration of the sleeve 27 is relatively higher. Overrun of the flywheel 22 occurs and the road wheel brake pressure is reduced by the balls 29 moving up inclined ramps 30 to cause axial movement of the sleeve member 27 to the right and uncover orifices 36 to permit air to pass via an axial bore 37 in the spindle 11, radial passages 38 in a seal 12 leading to an outlet passage 35 to a servo which reduces the braking effort applied to the wheel. The air for controlling the servo enters the housing 10 through a filter 33 positioned between the outer face of the end wall 20 of the housing and a protective cap 34. The air in the housing may pass to an outlet passage 35 in the end wall 14 of the housing to the servo which reduces the braking effort applied to the wheel.